As others have said, Star Control 2 doesn't really restrict itself to a single genre, instead borrowing from several. It is definitely not 4X, although Star Control 1 had some memorable strategic elements. The sequel was an open world action adventure borrowing elements of RPG (searching for artifacts and lengthy dialog-driven conversation to advance the plot), shoot-em-ups (ship-to-ship combat and collecting resources on planets), puzzle solving (navigating a vast interstellar map with limited time and resources), and basic strategy (deciding how to design and outfit your primary ship and which support ships you choose to represent your fleet).
All of these elements are incorporated very loosely into a whole without a specific focus on any one in particular. This went a long way toward making it more than the sum of its parts. You have a variety of responsibilities as the captain and are not restricted to just one aspect of gameplay. I think it's a big part of what gives it the literary aspects of an epic, while at the same time having enough levity to not take itself too seriously, as many modern games in these genres seem to.
